@Entity
public class Item {

  @Id
  @GeneratedValue(strategy = GenerationType.SEQUENCE)
  private long id;

  @Column
  private Instant timestamp1;

  @Column
  private LocalDateTime timestamp2;

  @Column(columnDefinition = "timestamp")
  private Instant timestamp3;

  @Column(columnDefinition = "TIMESTAMP WITH TIME ZONE")
  private LocalDateTime timestamp4;

  public long getId() {
      return id;
  }

  public void setId(long id) {
      this.id = id;
  }

  public Instant getTimestamp1() {
      return timestamp1;
  }

  public void setTimestamp1(Instant timestamp1) {
      this.timestamp1 = timestamp1;
  }

  public LocalDateTime getTimestamp2() {
      return timestamp2;
  }

  public void setTimestamp2(LocalDateTime timestamp2) {
      this.timestamp2 = timestamp2;
  }

}

@Entity
public class Item {

   @Id
   @GeneratedValue(strategy = GenerationType.SEQUENCE)
   @Getter
   @Setter
   private long id;

   @Column
   @Getter
   @Setter
   private Instant timestamp1;

   @Column
   @Getter
   @Setter
   private LocalDateTime timestamp2;

  ...

}